JP2004225669A - Sealing structure of fuel tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure of a fuel tank, which is easy to perform work of sealing an opening of the fuel tank, has a small number of parts and is excellent in sealing performance. <P>SOLUTION: The sealing structure of the fuel tank comprises a mounting part 16 integrally formed with a tank main body 12 by blow molding, and a sealing member 20 attached to the mounting part 16. The mounting part 16 comprises a mounting main body 16a of a cylindrical shape, a seal surface 16c formed on the mounting main body 16a, and a first engaging portion 18. The sealing member 20 seals the tank opening 12a with a seal member 30 interposed between the seal surface 16c and a supporting tube 23 and with a second engaging portion 25 engaged with the first engaging portion 18. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel tank sealing structure for closing a tank opening of a fuel tank.
[0002]
[Prior art and its problems]
2. Description of the Related Art Conventionally, as a sealing structure for a fuel tank of this type, there has been known a structure in which a tank opening is provided in a fuel tank, a piping port and valves are attached to the tank opening to connect with the outside, and seal the tank opening.
[0003]
For example, there is a technique in which a sealing member is formed of a resin material that can be thermally welded to a resin fuel tank, and this is joined to the fuel tank by thermal welding (Patent Document 1). Also, there is a technique in which a male screw is provided around a tank opening, and a sealing member is attached using a nut member screwed to the male screw (Patent Document 2).
[0004]
In the technique of Patent Document 1, the sealing member must be formed of a resin material that can be welded to the fuel tank, and thus not only has a low degree of freedom in material selection, but also requires a welding process, thereby reducing cost. Hindered. Further, in the technique of Patent Document 2, since a male screw or a nut member is used for screwing, there is a problem that the number of parts increases, which also hinders cost reduction.
[0005]
FIG. 13 is a cross-sectional view showing a fuel tank sealing structure according to another conventional technique. The tank upper wall 102 of the fuel tank 100 is heat-welded to the tank upper wall 102 and a separate cylindrical member 106 so as to surround the tank opening 104, and the sealing member 110 is further sealed between the cylindrical member 106 and the cylindrical member 106. There is also known a configuration in which snap fastening is performed on the cylindrical member 106 with the seal member 112 interposed therebetween (Patent Document 3). However, the resin material of the cylindrical member 106 is not limited to a material that can be welded to the tank upper wall 102, and there is a problem that the operation of welding the cylindrical member 106 to the tank upper wall 102 is troublesome.
[Patent Document 1]
JP 2002-293144 A [Patent Document 2]
JP 2002-114046 A [Patent Document 3]
JP 2001-113590 A
The present invention solves the above-mentioned problems of the prior art, and is simple in the work of mounting on the tank opening of the fuel tank, has a large degree of freedom in material selection, has a small number of parts, and has excellent sealing performance. An object of the present invention is to provide a sealing structure for a tank.
[0007]
[Means for Solving the Problems and Their Functions and Effects]
A tank body formed by blow molding and having a tank opening; a mounting portion formed integrally with the tank body by blow molding and formed so as to surround the tank opening; A sealing structure for a fuel tank, comprising: a sealing member that closes, a sealing member that seals between the tank opening and the sealing member,
The mounting portion has a substantially cylindrical mounting body projecting in a direction perpendicular to a wall surface of the tank main body, and a sealing surface provided on the cylindrical wall of the mounting main body and arranged so as to surround the tank opening. And a first engagement portion for attaching the sealing member,
An upper wall substantially covering the tank opening, a cylindrical support cylinder protruding from a lower surface of the upper wall and formed with a predetermined gap from the sealing surface; A second engaging portion that engages by elastically deforming the portion and attaches the sealing member to the mounting portion.
The sealing member seals the tank opening by interposing a sealing member between the sealing surface and the support cylinder and engaging the second engaging portion with the first engaging portion. It is characterized in that it is configured to perform.
[0008]
According to the fuel tank mounting structure of the present invention, since the mounting portion can be formed simultaneously with the tank body by blow molding, the number of parts can be reduced, and as described in the related art, the sealing member and There is no need for a step of welding the mounting portion, and the cost can be reduced.
[0009]
Also, since the sealing member is a separate member from the fuel tank, a resin material having a property different from that of the fuel tank, for example, a means of applying a resin material having excellent fuel permeability resistance can be used. High degree of freedom in material selection.
[0010]
Further, the sealing member can be attached to the fuel tank with one touch by elastically deforming the second engaging portion and engaging the first engaging portion of the fuel tank, so that the attaching operation is simple.
[0011]
In addition, since the sealing surface is provided on the cylindrical wall surface, even if it is formed to be twisted in the axial direction or the circumferential direction, distortion such as waving is small. Therefore, high surface accuracy can be obtained for the sealing surface even by blow molding.
[0012]
As a preferred embodiment of the present invention, the tank main body is formed of a resin material which is provided between the tank inner layer, the tank outer layer, and between the tank inner layer and the tank outer layer and has higher fuel permeability than the tank inner layer and the tank outer layer. And a barrier layer formed along the sealing surface in the mounting portion. With this configuration, the barrier layer is disposed over substantially the entirety of the mounting portion, so that permeation of fuel vapor can be prevented. In this case, by extending the end of the barrier layer exposed to the tank opening from the sealing member to the tank body side, the mounting portion and the periphery of the tank opening are sealed by the barrier layer and the sealing member. Further, the fuel permeation resistance can be further improved.
[0013]
Further, as a preferable aspect of the mounting portion, a configuration can be adopted in which a reinforcing member for preventing deformation of the sealing surface is provided on an outer peripheral portion of the mounting main body. With this configuration, even if the sealing surface receives a large force from the sealing member, the reinforcing member is prevented from distorting the sealing surface, and the sealing performance is improved. The reinforcing member may be insert-molded on the outer peripheral portion of the mounting body to enhance the integration with the mounting portion.
[0014]
Further, one end of the reinforcing member may include a first engagement portion that engages with the second engagement portion. In this case, by forming the reinforcing member from a material having higher mechanical strength than the resin material of the mounting portion, for example, a metal material or a hard resin, the second engaging portion can be firmly engaged.
[0015]
Further, as a preferable aspect of the first engagement portion and the second engagement portion, a configuration may be adopted in which a detachment restriction member that hides the engagement portion from the outside of the tank body is provided. With this detachment restricting member, it is possible to prevent the user from accidentally removing it.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
A. First Embodiment (1) Schematic Configuration of Fuel Tank Sealing Structure FIG. 1 is a sectional view showing a fuel tank sealing structure according to a first embodiment of the present invention. This embodiment is an example applied to a sealing member 20 having a piping port for connecting a fuel tank 10 of an automobile to the outside. The sealing member 20 is configured to be detachably mounted on the mounting portion 16 of the fuel tank 10 to seal the tank opening. Hereinafter, the configuration of each unit will be described in detail.
[0017]
(2) -1 Configuration of Fuel Tank 10 FIG. 2 is a sectional view showing a state before the sealing member 20 is attached to the fuel tank 10. In FIG. 2, the fuel tank 10 is formed in three layers by a blow molding method from a composite resin material containing polyethylene (PE). That is, the fuel tank 10 is formed by stacking the tank inner layer 13a, the tank outer layer 13b, and the barrier layer 13c interposed between the tank inner layer 13a and the tank outer layer 13b. The tank inner layer 13a and the tank outer layer 13b are formed of high-density polyethylene, and mainly have a function as a structural material for ensuring the mechanical strength of the fuel tank. On the other hand, the barrier layer 13c is formed of ethylene vinyl alcohol (EVOH) or polyamide (PA) having excellent resistance to fuel permeation, and has a function as a shielding material for preventing permeation of fuel vapor.
[0018]
A mounting portion 16 for mounting the sealing member 20 is provided on the tank upper wall 14 of the fuel tank 10. The mounting portion 16 includes a mounting main body 16 a protruding from the tank upper wall 14. A flange 16b is formed on an upper portion of the mounting body 16a. The lower end of the flange 16b serves as a first engagement portion 18 for attaching the sealing member 20. The mounting body 16a has a substantially cylindrical shape, and includes a sealing surface 16c formed of a cylindrical surface on an inner peripheral portion thereof. Further, a tank opening 12a formed by cutting the tank body 12 into a circular shape with a cutter or the like is provided below the mounting portion 16. Assuming that the diameter of the cylindrical surface formed by the sealing surface 16c is D1, and the diameter of the tank opening 12a is D2, D1> D2. In other words, the tank opening 12a forms a projecting portion projecting annularly from the lower portion of the sealing surface 16c, and the upper surface of the peripheral edge serves as a stopper surface 12b for stopping the sealing member 30.
[0019]
(2) -2 Manufacturing Process of Fuel Tank 10 The fuel tank 10 is manufactured by a blow molding method. FIG. 3 is an explanatory diagram for explaining the blow molding method. The blow molding method is performed using the molding device 50. The molding device 50 has molding dies 51 and 52 for forming a cavity. The molding die 51 is formed with molding surfaces 53 and 54 that follow the outer wall of the tank body 12 (see FIG. 1). On one molding surface 53, an annular recess 55 and a circular protrusion 56 for forming the mounting portion 16 (see FIG. 1) are formed. Now, the parison PS is installed in the cavity between the molds 51 and 52. As the parison PS, a laminate of three resin layers serving as the tank inner layer 13a, the tank outer layer 13b, and the barrier layer 13c shown in FIG. 1 is used. When the compressed gas is blown into the parison PS after the mold is clamped, the parison PS forms the tank body 12 following the molding surfaces 53 and 54. At this time, as shown in FIG. 4, a part of the parison PS forms the attachment portion 16 by following the annular recess 55 and the circular protrusion 56, and the barrier layer 13c is formed along the shape of the attachment portion 16. Bendable. Subsequently, as shown in FIG. 5, the tank opening 12a is formed by cutting the bottom of the mounting portion 16 with the cutter CT. At this time, by setting the diameter of the tank opening 12a to be smaller than the diameter D1 of the sealing surface 16c, a stopper surface 12b is formed on the upper peripheral surface of the tank opening 12a. Thereby, the tank body 12 is manufactured.
[0020]
(3) -1 Configuration of Sealing Member 20 Returning to FIG. 2, the sealing member 20 is a joint for closing the tank opening 12a of the fuel tank 10 and connecting to the hose H. A connection pipe 24 protruding from an upper portion of the sealing body 21; The sealing body 21 includes a disk-shaped upper wall 22 and a support cylinder 23 projecting from the lower surface of the upper wall 22. A flange 22 a is formed on an outer peripheral portion of the upper wall 22. At the lower end of the flange 22a, a plurality of (three to four) second engagement portions 25 are formed at equal intervals in the circumferential direction. The second engaging portion 25 has an arm 25a and a claw 25b formed at the tip of the arm 25a, and the claw 25b engages with the first engaging portion 18 of the mounting portion 16 to form a seal. The member 20 is mounted on the mounting portion 16.
[0021]
The support cylinder 23 projects from the lower surface of the upper wall 22 in a cylindrical shape, and seal members 30, 30 are mounted on the outer peripheral portion thereof while being supported by spacers 32, 32. Different materials can be used for the sealing members 30, 30 according to the sealing performance. For example, trifluoropropyl methyl siloxane condensate (FVMQ) is used for one, and fluoro rubber (FKM) is used for the other. Can be.
[0022]
The connection pipe 24 is an L-shaped pipe having a connection passage 24a, and a hose H is connected to the connection end 24b. The connection passage 24a is arranged from the center of the sealing body 21 to the connection end 24b, and connects the inside of the fuel tank 10 and the hose H.
[0023]
(3) -2 Attaching operation of sealing member 20 In order to attach the sealing member 20 to the mounting portion 16 of the fuel tank 10, the following operation is performed. First, the seal member 30 and the spacer 32 are sequentially inserted around the outer periphery of the support cylinder 23 of the sealing member 20, and are inserted from the lower end of the support cylinder 23 toward the tank opening 12a. When the claw 25b of the second engaging portion 25 hits the outer periphery of the flange 16b, it expands outward in the radial direction, and engages with the first engaging portion 18 by further insertion. Thereby, the sealing member 20 is attached to the attachment portion 16.
[0024]
In this state, the sealing members 30, 30 mounted on the outer periphery of the support cylinder 23 of the sealing member 20 are pressed against the sealing surface 16c to seal the gap therebetween, thereby allowing the inside of the fuel tank 10 to move to the outside. Shut off.
[0025]
(4) Functions and Effects of the Fuel Tank Sealing Structure According to the above fuel tank sealing structure, the following functions and effects are exhibited in addition to the above-described functions and effects.
[0026]
(4) -1 Since the mounting portion 16 can be formed simultaneously with the tank body 12 by blow molding, the number of parts can be reduced, and the sealing member and the mounting portion can be formed as described in the related art. There is no need for a welding step, and the cost can be reduced.
[0027]
(4) -2 Since the sealing member 20 is a separate member from the fuel tank 10, means for applying a resin material having a property different from that of the fuel tank 10, for example, a resin material having excellent fuel permeability resistance is used. And the degree of freedom in material selection is high.
[0028]
(4) -3 The sealing member 20 can be attached to the fuel tank 10 with one touch by elastically deforming the second engaging portion 25 and engaging the first engaging portion 18 of the fuel tank 10. The installation work is simple.
[0029]
(4) -4 Since the seal surface 16c can be blow-molded with high surface accuracy on the mounting portion 16, the sealability is excellent. That is, as shown in FIG. 6, when the parison PS is made to follow the molding surface 53 in blow molding, the parison PS extends toward the molding surface 53 and contracts in the direction opposite to the direction in which the parison PS extended during cooling. At this time, the upper surface Us of the mounting portion 16 contracts in the direction d1 and the range of the parison affecting the contraction is L1, whereas the sealing surface 16c contracts in the direction d2. The range of the parison that affects its contraction is L2. Therefore, when a sealing surface is formed on the upper surface Us, a high sealing property cannot be obtained due to the effect of resin shrinkage, but by sealing with the sealing surface 16c having a small range that affects shrinkage during blow molding, High surface accuracy can be obtained.
In addition, since the sealing surface 16c is provided on the inner surface of the cylinder, even if it is formed to be twisted in the axial direction or the circumferential direction, distortion such as waving is small. Therefore, the seal surface 16c can obtain high surface accuracy even by blow molding.
[0030]
(4) -5 The barrier layer 13c follows the raised shape of the mounting portion 16 in the mounting portion 16 and is disposed along the sealing surface 16c, and the portion 12d exposed to the tank opening 12a is a sealing member. Since the fuel cell 10 is disposed inside the fuel tank 10 from the position 30, there is no portion that is not covered by the barrier layer 13 c around the tank opening 12 a, and the fuel permeation resistance is excellent.
[0031]
B. Second Embodiment FIG. 7 is a sectional view showing a fuel tank sealing structure according to a second embodiment of the present invention. In FIG. 7, at the lower end of the support cylinder 23B, three to four second engagement portions 25B are formed at equal intervals in the circumferential direction. The lower surface of the projecting portion of the tank opening 12a is a first engaging portion 18B having a ring-shaped plane. That is, the overhanging portion forms the stopper surface 12b that supports the seal member 30 on the upper surface, and the first engagement portion 18B for engaging the second engagement portion 25B of the sealing member 20B on the lower surface. Has formed. According to this configuration, since the second engagement portion 25B is located below the seal member 30 and cannot be removed from the outside, the second engagement portion 25B is not accidentally removed by the user.
[0032]
C. Third Embodiment FIG. 8 is a sectional view showing a fuel tank sealing structure according to a third embodiment of the present invention. An annular reinforcing member 36 is provided on the outer periphery of the mounting portion 16C. The reinforcing member 36 is formed of a metal or a hard resin [for example, polyacetal (POM)]. The reinforcing member 36 prevents the sealing surface 16c from being distorted even when a large force is applied from the sealing member 30, and improves the sealing performance.
[0033]
In addition, as shown in FIG. 9, the reinforcing member 36D may be integrated with the outer peripheral portion of the mounting portion 16D by insert molding to increase the bonding force with the mounting portion 16D. Further, as shown in FIG. 10, a first engaging portion 18E may be provided on the reinforcing member 36E so as to engage the second engaging portion 25E of the sealing member 20E. As described above, the first engagement portion 18F may be provided in the gap between the reinforcing member 36F and the flange 22Fa, and the second engagement portion 25F of the sealing member 20F may be configured to be engaged.
[0034]
D. Fourth Embodiment FIG. 12 is a sectional view showing a fuel tank sealing structure according to a fourth embodiment of the present invention. In FIG. 12, a detachment restricting member 38 is attached to the outer peripheral portion of the second engaging portion 25G of the sealing member 20G. The disengagement restricting member 38 hides an engagement portion between the second engagement portion 25G and the first engagement portion 18G from the outside. The detachment restricting member 38 protects the second engagement portion 25G against external impact, prevents the engagement from being released, and further prevents the user from being inadvertently released. Can be.
[0035]
The present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist of the present invention. For example, the following modifications are possible.
[0036]
(1) In the above embodiment, the O-ring is used as the seal member. However, the present invention is not limited to this. Any structure may be used as long as it seals between the seal surface 16c and the support cylinder 23. A cylindrical rubber packing may be used.
[0037]
(2) In the above embodiment, an example in which the fuel tank is applied to a piping port for connecting the fuel tank to the outside has been described. However, the present invention is not limited to this. The present invention can also be applied to a joint to an inlet pipe for supplying fuel.
[0038]
(3) In the above embodiment, the sealing surface is provided on the inner wall of the cylinder of the mounting body, but is not limited to this, and may be an outer wall of the cylinder. This configuration can be realized by providing a sealing member on the sealing surface of the outer wall and pressing the sealing member with the sealing member. In this case, if the sealing member is formed of a resin material having a smaller fuel swelling property than the tank body, as the mounting portion swells with fuel and expands in diameter, the force for pressing the sealing member with the sealing member increases. Since it becomes large, the sealing property can be improved.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a fuel tank sealing structure according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing a state before a sealing member is attached to a fuel tank.
FIG. 3 is an explanatory view illustrating a blow molding step.
FIG. 4 is an explanatory view illustrating a blow molding step following FIG. 3;
FIG. 5 is an explanatory diagram illustrating a manufacturing process of the fuel tank.
FIG. 6 is an explanatory diagram for explaining an operation on a sealing surface by a blow molding process.
FIG. 7 is a sectional view showing a fuel tank sealing structure according to a second embodiment of the present invention.
FIG. 8 is a sectional view showing a fuel tank sealing structure according to a third embodiment of the present invention.
FIG. 9 is a cross-sectional view according to a modification of the third embodiment.
FIG. 10 is a sectional view showing another modification of the third embodiment.
FIG. 11 is a sectional view showing another modification of the third embodiment.
FIG. 12 is a sectional view showing a fuel tank sealing structure according to a fourth embodiment.
FIG. 13 is a cross-sectional view showing a fuel tank sealing structure according to a conventional technique.
[Explanation of symbols]
10. . . Fuel tank 12. . . Tank body 12a. . . Tank opening 12b. . . Stopper surface 12d. . . Part 13a. . . Tank inner layer 13b. . . Tank outer layer 13c. . . Barrier layer 14. . . Tank upper wall 16. . . Mounting part 16C. . . Mounting part 16D. . . Attachments 16a. . . Mounting body 16b. . . Flange 16c. . . Seal surface 18. . . The first engagement portion 18B. . . The first engagement portion 18E. . . The first engagement portion 18F. . . The first engagement portion 18G. . . First engagement portion 20. . . Sealing member 20E. . . Sealing member 20F. . . Sealing member 20G. . . Sealing member 21. . . Sealing body 22. . . Upper wall 22a. . . Flange 22Fa. . . Flange 23. . . Support cylinder 23B. . . Support cylinder 24. . . Connection tube 24a. . . Connection passage 24b. . . Connection end 25. . . The second engagement portion 25B. . . Second engagement portion 25E. . . Second engagement portion 25F. . . Second engagement portion 25G. . . The second engagement portions 25a. . . Arm 25b. . . Nail 30. . . Seal member 32. . . Spacer 36. . . Reinforcing member 36D. . . Reinforcing member 36E. . . Reinforcing member 36F. . . Reinforcement member 38. . . Detachment regulating member 50. . . Molding devices 51, 52. . . Molds 53, 54. . . Molding surface 55. . . Annular recess 56. . . Circular protrusion CT. . . Cutter H. . . Hose PS. . . Parison

Claims (4)

A tank body (12) formed by blow molding and having a tank opening (12a); and a mounting portion formed integrally with the tank body (12) by blow molding and surrounding the tank opening (12a). (16), a sealing member (20) mounted on the mounting portion (16) and closing the tank opening (12a), and a seal between the tank opening (12a) and the sealing member (20). And a sealing member (30) for sealing the fuel tank, comprising:
The mounting portion (16) is provided on a substantially cylindrical mounting body (16a) projecting in a direction perpendicular to the wall surface of the tank body (12), and on a cylindrical wall of the mounting body (16a); A sealing surface (16c) arranged so as to surround the tank opening (12a), and a first engagement portion (18) for attaching the sealing member (20);
The sealing member (20) protrudes from the lower surface of the upper wall (22) and substantially covers the tank opening (12a), and is formed with a predetermined gap from the sealing surface (16c). A second supporting member (23), which is engaged with the first engaging portion (18) by being elastically deformed to attach the sealing member (20) to the mounting portion (16). An engagement portion (25);
The sealing member (20) interposes the sealing member (30) between the sealing surface (16c) and the support cylinder (23), and connects the second engaging portion (25) to the sealing member (30). (1) A fuel tank sealing structure, wherein the tank opening (12a) is sealed by engaging with an engagement portion (18). The sealing structure for a fuel tank according to claim 1,
The tank body (12) includes a tank inner layer (13a), a tank outer layer (13b), and a tank inner layer (13a) and a tank outer layer (13b) interposed between the tank inner layer (13a) and the tank outer layer (13b). And a barrier layer (13c) formed of a resin material having more excellent fuel permeability resistance. The barrier layer (13c) is formed along the sealing surface (16c) in the mounting portion (16). Fuel tank sealing structure. In the fuel tank sealing structure according to claim 1 or 2, the mounting portion (16) is provided on an outer peripheral portion of the mounting body (16a) with a reinforcing member for preventing deformation of the sealing surface (16c). 36) A sealing structure for a fuel tank comprising: In the fuel tank sealing structure according to any one of claims 1 to 3,
A fuel tank sealing structure provided with a detachment restricting member (38) for hiding an engagement portion between the first engagement portion (18) and the second engagement portion (25) from the outside of the tank body (12).

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